| RIA | Radio Immuno-Assay 
| Others |
| RIA | Radio-ImmunoAssay
| Others |
| RIA | Radioactive Immunoassay
| Others |
| RIA | RadioImmunoAssay
| Others |
| RIA | Rapid Impact Analysis
| Others |
| RIA | Rare Isotope Accelerator
| Others |
| RIA | Really Interesting Architecture
| Others |
| RIA | Referentie Interconnectie Aanbieding
| Others |
| RIA | Regional Integration Agreement
| Others |
| RIA | Registered Investment Adviser
| Others |
| RIA | Registered Investment Advisor
| Others |
| RIA | Registered Investment Advisors
| Others |
| RIA | Regulatory Impact Analysis
| Others |
| RIA | Regulatory Impact Assessment
| Others |
| RIA | Relay Interface Adapter
| Others |
| RIA | Research and Innovation Action
| Others |
| RIA | Research and Innovation Actions
| Others |
| RIA | Research Institute of America
| Others |
| RIA | Research Institute on Addictions
| Others |
| RIA | Residential Inspector of America
| Others |
| RIA | Residual Intangible Assets
| Others |
| RIA | Restoration Industry Association
| Others |
| RIA | Revista Inginerilor de Automobile
| Others |
| RIA | Rhode Island Avenue
| Others |
| RIA | Rhydin Intelligence Agency
| Others |
| RIA | Ricambi Per l'Industria Automobilistica
| Others |
| RIA | Rich Internet Application
| Others |
| RIA | Rich Internet applications
| Others |
| RIA | Road Safety Impact Assessment
| Others |
| RIA | Robotic Industries Association
| Others |
| RIA | Robotics Industries Association
| Others |
| RIA | Rock Island Arsenal
| Others |
| RIA | Royal Irish Academy
| Others |
| RIA | Rural Infrastructure Authority
| Others |
| RIA | Santa Maria, Rio Grande do Sul, Brazil
| Others |